A high-frequency high-Q CMOS active inductor with DC bias control

The design of a very simple CMOS high-Q active inductor suitable for applications at low supply voltage and high frequencies is discussed. The inductor value, L, and the quality factor, Q, are independently adjustable by two PMOS varactors (variable capacitors). Alternatively, L can be tuned via a bias current. The inductor´s DC level is set by a bias voltage. The self-resonance frequency, f/sub r/, is larger than 1GHz and very high values of Q, up to Q=/spl infin/, can be obtained so that circuit can be used for constructing high-frequency oscillators. The performance of the electronic inductor is demonstrated by simulation.